To ensure the safety and stability of cement improved aeolian sand subgrades throughout their service life, the macroscopic mechanical properties and microscopic damage characteristics of improved aeolian sand with different cement contents were investigated using unconfined compression tests, acoustic emission(AE) monitoring, and discrete element numerical simulation. The curing mechanism and microstructural evolution were analyzed through Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The results indicate that as the cement content increases, the strength of the improved aeolian sand gradually improves, with a significant increase in material stiffness observed at 8% cement content. Acoustic emission ring counts exhibit a high-low-high-low fluctuation pattern, with the overall failure process dominated by tensile cracking. Microcracks initiate during the plastic yield stage and rapidly propagate during the failure stage. Increasing cement content reduces particle displacement, inhibits the initiation and propagation of microcracks, and consequently decreases the extent of macroscopic failure. Microscopic analysis reveals that higher cement content promotes the formation of hydration products that bind and connect fine particles and sand grains, reducing both pore number and size. This effect is especially pronounced when the cement content is at least 8%. These findings provide a theoretical foundation and technical guidance for material proportioning and damage monitoring of cement-stabilized aeolian sand in desert subgrade engineering.